Telescope Reviews: Short evening with doubles

I had yesterday another (not) so short session with doubles. This time I was trying to explore the capabilities of my new AS110/1650. Also during the observation, I had no idea about doubles PA.

I started with a warm-up, epsilon Boo. Beautiful clear split and very nice colors, especially the secondary was quite blue. Warm-up was indeed needed. Performing star test on Izar revealed quite strong spherical aberration. Fortunately, it was gone withing next 20 minutes and the star test was almost perfect. But in-focus image still was showing some brightening in the 1st diffraction ring at PA~240deg during the whole session. This was quite confusing later on when I was hunting for more difficult pairs.

Another warm-up double was delta Cygni. This one required some attention with focusing but once it was done properly, the secondary was clearly visible all the time.

Then I jumped to 75 Cyg (5.3+10.1, 2.7"). This was very difficult but at short moments I could glimpse at 180x (Baader ortho 9mm) very faint point at PA~340deg. I confirmed the observation at 240x (TMB Mono 7mm).

Next, 60 Cyg (5.4+9.5, 2.9") was still difficult but much more relaxing than 75 Cyg.

Mu Cygni was very nice sight and then I switched to 2 Vul (5.4+8.8, 1.7"). This one was again very difficult. I got myself sure only after observing it at 275x (CZJ O-6).

I had no luck with 13 Del (5.6+8.2, 1.5") - here I got fooled by the brightening at 1st diffractive ring at PA~240deg.

I tried again lambda Cyg (4.7+6.3, 0.9") - again nicely visible small bump at PA~0deg on the bright circle.

Then I went even for more tight pair - 16 Vul. Here I could see just prolonged image of one star with PA~130deg. I was using magnifications up to 400x, to clearly see the alongation.

Then there was a series of unsuccessful attempts to crack pi Cep (4.6+6.8, 1.1"), 6 Cas (4.7+8.0, 1.5") and STT457 (6.0+8.2, 1.3"), and one successful and relatively easy split, STF2950 (6.0+7.1, 1.3").

I finished the 2.5 hour session with admiring xi Cep (4.4+6.4, 7"). It was lovely and bright white pair at 41x.